1. Field of the Invention
The present invention relates to a semiconductor memory device and a method of manufacturing the semiconductor memory device, and is applied, for example, to a NAND flash memory.
2. Description of the Related Art
Semiconductor memory devices, for instance, NAND flash memories, have recently begun to be used as main memories of various electronic apparatus such as portable audio equipment, by virtue of their features of large capacity and nonvolatility (see, e.g. Jpn. Pat. Appln. KOKAI Publication No. H8-55920).
When active areas of the NAND flash memory are to be formed on a semiconductor substrate, each of the active areas is formed with an isolated pattern in a line shape along one direction.
Thus, “tapering” or “cracking” may occur at a one-side terminal end portion and at the other-side terminal end portion of the active area, and, consequently, dust occurs. As a result, a dust defect due to such dust tends to occur. In addition, there is a tendency that the manufacturing yield decreases due to the dust defect.